An Anytime Valid Test for Complete Spatial Randomness

Fuente: arXiv
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Auteurs principaux: Dixit, Vaidehi, Wikle, Christopher K., Holan, Scott H.
Format: Preprint
Publié: 2025
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author Dixit, Vaidehi
Wikle, Christopher K.
Holan, Scott H.
author_facet Dixit, Vaidehi
Wikle, Christopher K.
Holan, Scott H.
contents A relevant question when analyzing spatial point patterns is that of spatial randomness. More specifically, before any model can be fit to a point pattern a first step is to test the data for departures from complete spatial randomness (CSR). Traditional techniques employ distance or quadrat counts based methods to test for CSR based on batched data. In this paper, we consider the practical scenario of testing for CSR when the data are available sequentially (i.e., online). We present a sequential testing methodology called as {\em PRe-process} that is based on e-values and is a fast, efficient and nonparametric method. Simulation experiments with the truth departing from CSR in two different scenarios show that the method is effective in capturing inhomogeneity over time. Two real data illustrations considering lung cancer cases in the Chorley-Ribble area, England from 1974 - 1983 and locations of earthquakes in the state of Oklahoma, USA from 2000 - 2011 demonstrate the utility of the PRe-process in sequential testing of CSR.
format Preprint
id arxiv_https___arxiv_org_abs_2504_02960
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An Anytime Valid Test for Complete Spatial Randomness
Dixit, Vaidehi
Wikle, Christopher K.
Holan, Scott H.
Other Statistics
A relevant question when analyzing spatial point patterns is that of spatial randomness. More specifically, before any model can be fit to a point pattern a first step is to test the data for departures from complete spatial randomness (CSR). Traditional techniques employ distance or quadrat counts based methods to test for CSR based on batched data. In this paper, we consider the practical scenario of testing for CSR when the data are available sequentially (i.e., online). We present a sequential testing methodology called as {\em PRe-process} that is based on e-values and is a fast, efficient and nonparametric method. Simulation experiments with the truth departing from CSR in two different scenarios show that the method is effective in capturing inhomogeneity over time. Two real data illustrations considering lung cancer cases in the Chorley-Ribble area, England from 1974 - 1983 and locations of earthquakes in the state of Oklahoma, USA from 2000 - 2011 demonstrate the utility of the PRe-process in sequential testing of CSR.
title An Anytime Valid Test for Complete Spatial Randomness
topic Other Statistics
url https://arxiv.org/abs/2504.02960